Regulating system for winding devices for threads or threadlike structures



N v- ,1970 HISCHIPPERS ETAL 3,537,660

REGULATING SYSTEM FOR WINDING DEVICES FOR THREADS 0R THREADLIKESTRUCTURES Filed Aug. 17, 1967 2 Sheets-Sheet 1 mvemoas: HEINZ SCHIPPERSHANS LOHEST WOLFGANG WEBER ERICH LENK ATT'YS ,1970 H. SCHIPPERS ETAL3,537,660

- REGULATING SYSTEM FOR WINDING DEVICES FOR THREADS OR THREADLIKESTRUCTURES Filed Aug. 17, 1967 2 Sheets-Sheet 2 INVENTORS'.

HEINZ SCHIPPERS HANS LOHEST WOLFGANG WEBER- ERICH LENK United StatesPatent 01 lice 3,537,660 REGULATING SYSTEM FOR WINDING DEVICES FORTHREADS R THREADLIKE STRUCTURES Heinz Schippers and Hans Lohest,Remscheid-Lennep, Wolfgang Weber, Wuppertal-Elberfeld, and Erich Lenk,Remscheid-Lennep, Germany, assignors to Barmag Barmer MaschinenfabrikAG., Wuppertal, Germany Filed Aug. 17, 1967, Ser. No. 661,430 Claimspriority, appliclzgltig iyl s(icrmany, Aug. 18, 1966,

Int. (:1. B6511 59/38 U.S. (:1. 242-45 4 Claims ABSTRACT OF THEDISCLOSURE This invention relates to winding devices and, moreparticularly, to apparatus for suppressing variations in thread tensionduring winding operations.

In winding operations, it is essential that the thread or other materialbeing wound is maintained at a substantially constant tension in orderto achieve a uniform product. It is, therefore, necessary to monitor andcontrol thread tension and to make adjustments when the tension variesfrom some predetermined value. Obviously, it is most desirable to havethe monitoring and regulation of thread tension accomplishedautomatically during the winding process.

It is a known practice to use a sensing lever to determine threadtension or winding diameter. The sensing lever is used in conjunctionwith a rotary transformer to regulate or control drive motor speeds. Inaddition, servo motor control has been proposed for winding drives. Theservomotor, operating in conjunction with an inductive pickup, transmitsan electrical signal, corresponding to the magnitude of the sensinglever deflection, to the winding drive control circuitry. This systemtends, as experience has shown, to pendulate or oscillate, since theinductive pickup has ordinarily not returned to its zero or nullposition at the time the drive motor has been regulated to the properspeed, and consequently, the drive motor receives further controlimpulses causing an overcorrection. In order to avoid this pendulationand to achieve a proportional-integral regulation, it has been proposedto control the servomotor over a potentiometer. The con-' trol windingof the servomotor lies in the zero branch of a bridge circuit and isconnected to an auxiliary voltage between the inductive pickup and aresistor on the one hand and a potentiometer tap on the other. The useof such a potentiometer continuously operated by a servomotor bringsabout a severe wear on this element.

It is therefore an object of the present invention to provide acompletely contactless, simple, maintenance free system for theregulation of winding or spooling drives as a function of threadtension.

It is a further object of this invention to provide a system for theregulation of winding or spooling drives which is free from pendulationor overcontrolling tendencies.

In general, the present invention consists of apparatus for regulatingwinding drives to achieve a substantially 3,537,660 Patented Nov. 3,1970 constant thread tension. In one embodiment of the invention asensing lever is situated in a thread loop. The thread loop is arrangedsuch that the depth of the loop is a function of the thread tension.Variations in thread tension as indicated by corresponding variations inloop depth are transmitted by means of the sensing lever to acontactless generator. The contactless generator consists of a rotarytransformer, one winding of which is connected to the alternatingcurrent main; the other winding being connected to the input of anamplifier of conventional design. The displacement of the sensing leveris transformed in the rotary transformer into a proportional orapproximately proportional electrical control current. This controlcurrent is amplified and passed to the input of a thyristor circuit orother transducer. The output side of the thyristor circuit is connectedto the take-up spool drive motor. The thyristor circuit, which is alsoconnected to the alternating current main, rectifies the alternatingcurrent and passes the resulting direct current to the drive motor.Variations in control current fed to the input of the thyristor circuitcause corresponding changes in current delivered to the drive motor, andaccordingly, in drive motor speed. Consequently, variations in threadtension cause the drive motor speed to be altered such that the threadtension tends to remain constant.

This arrangement presents considerable advantage over the knownregulating or controlling devices. For example, the load on the rotarytransformer windings is very low, and accordingly the torque associatedwith displacement of the rotary transformer winding is low. In contrast,displacement of a rotary transformer winding which carries motor feedcurrent, causes a great load on the thread. Similarly, the presentinvention dispenses with both a servomotor and potentiometer. Moreover,the regulating system, thus simplified, is, because of the use ofcontactless structural elements, less subject to breakdown. Further, byusing the rotary transformer as a contactless generator instead of aregulating transformer, no mechanical wear takes place. In addition,although the contactless generator is specified above as a rotarytransformer, a semiconductor, whose electrical conductivity is variableby light or magnetic or electrical fields, can be used instead.

Various modes of regulation may be obtained by providing, in theregulating circuit of the sensing lever or other sensing device, amechanical-pneumatic damping or regulating member withproportional-integral behavior and/or differentiating rate-timebehavior. This damping or regulating member can be coupled or securelyconnected to the sensing lever or other sensing device. The damping orregulating member is designed in such a way that it brings about a rapidand desired modification of the drive motor speed to compensate for achange in thread tension and automatically regulates the tension back toits normal value.

It is further proposed to use the damping or regulating member with anaxially movable feeler prong which is adjustably biased by means of aspring and pneumatic piston and cylinder arrangement. The feeler prongis connected over a hinged lever and rod system to the control member ofan inductive generator. In the lever rod system, both spring andadjustable pneumatic forces are powers, it is also possible inaccordance with the present invention to utilize an alternating currentdrive motor in conjunction with two thyristors arranged in an inverseparallel circuit with an alternating current output, or with a triac ortransducer with alternating current output. The drive motor isconstructed as an alternating current slip rotor motor with raised rotorresistance. The two thyristor circuit, the triac or the transducer,whichever is utilized, is arranged between the amplifier and the drivemotor. Here, the use of the triac or transducer is to be peferred overthe two thyristors, since the triac and the transducer are supplied assingle structural elements.

The invention can be more fully understood by reference to the attacheddrawings which contain schematic representations of various embodimentsof the invention:

FIG. 1 shows the regulating system of a winding device wherein the speedof the direct current drive motor is controlled as a function of threadtension;

FIG. 2 shows the regulating system of a winding device wherein the speedof the alternating current drive motor is controlled as a function ofthread tension;

FIG. 3 shows the applications of a damping or regulating member in thesystem described in connection with FIG. 1;

FIG. 4 shows the application of a damping or regulating member in thesystem described in connection with FIG. 2; and

FIG. 5 shows an example of the execution of the damping or regulatingmember.

In FIG. 1, thread 1 passes over deflection rollers 2 and 3 and is woundon spool 4. Dancer roller 5 is arranged to reside on thread 1 betweenrollers 2 and 3. Dancer roller 5 is mounted on one end of swinging arm6. The other end of arm 6 is attached to rotor shaft 7. Rotor shaft 7 isturnable only through an angle of about 90. Rotor 8, which is mounted onrotor shaft 7, and stator 9 are the principal components of acontactless rotary transformer, used in known manner as an inductiongenerator (a device for converting position changes to electricalimpulses). Stator 9 is connected over terminals 10 and 11 to lines 12and 13 of the alternating current main. Rotor 8 is electricallyconnected through spiral springs 14 and 15 and lines 16 and 17 to theinput of amplifier 18. Spiral springs 14 and 15 are arranged on rotorshaft 7 such that one spring is situated clockwise about shaft 7 and theother spring is situated counterclockwise about shaft 7. Amplifier 18 isconnected to lines 12 and 13 of the alternating current main throughlines 19 and 20. The output of amplifier 18 provides control current tothyristor circuit 21 over lines 22 and 23. Thyristor circuit 21 drawsenergy from lines 12 and 13 of the alternating current main overconductors 24 and 25. The output of thyristor circuit 21 is connectedover conductors 26 and 27 to the armature circuit 28 of drive motor 29.Drive motor 29, which provides the rotational power for spool 4, can bea conventional type direct current motor. Preferably, however, abrushless direct current motor is used wherein electronic commutation isemployed thereby eliminating the wear points present in a brush typemotor. Field winding 30 of the drive motor 29 is externally excited withdirect current supplied over leads 31 and 32 from rectifier 33.Rectifier 33 receives its input current from leads 12 and 13 of thealternating current main through conductors 34 and 35. In normaloperation, thread 1 is wound on spool 4 driven by motor 29. Thread 1passes over deflection rollers 2 and 3 and forms a loop under the weightof dancer roller 5. The length of this loop varies according to threadtension. If, for example, the thread tension decreases, then the threadloop lengthens, and the dancer roller 5 follows the bottom of the loopcausing swinging arm 6 to turn rotor shaft 7 on its longitudinal axisclockwise through a small angle. Rotor 8 mounted on rotor shaft 7 willturn through a correspondingly small angle with respect to stator 9. Thecurrent induced in rotor 8 now changes and flows in correspondinglymodified magnitude to amplifier 18. The amplified current passes overconductors 22 and 23 to thyristor circuit 21 which controls the armaturecurrent of motor 29. Thyristor circuit 21 rectifies the alternatingcurrent fiowing in conductors 24 and 25 and delivers the resultingdirect current to armature circuit 28 over conductors 26 and 27. Thearmature current is therefore modified in accordance with the variationin amplified control current delivered to thyristor circuit 21 causing acorresponding change in drive motor speed. Spool 4, driven more rapidlyin this manner, now draws off the thread with a higher tension. Thethread loop shortens and the whole process is repeated in the reversedirection. The regulation takes place whenever the position of swingingarm 6, and, simultaneously, rotor 7 deviates from a certain desiredvalue. The corrective regulation continues until the actual value ofthread tension agrees with the desired value. It should be noted thatwhile FIG. 1 shows the power source as single phase alternating current,three phase current may also be utilized.

FIG. 2 is a schematic representation of a thread winding system using analternating current drive motor. Thread 1 passes over deflection rollers2 and 3 and is wound on spool 4. One end of an axially slidable feelerprong 36 is arranged to contact thread 1 as shown. Semiconductor 38,which is situated generally within the magnetic field of magnet 37, ismounted on the other end of prong 36. Semiconductor 38 which serves as acontactless pickup or sensor, will undergo variations in its electricalconductivity as it is moved into the field of magnet 37. Semiconductor38 is electrically connected through leads 39, 40, 16 and 17 to theinput of amplifier 18. Amplifier 18 obtains its power from leads 12 and13 of the three phase alternating current main through connections 19and 20. The output of amplifier 18 provides control current over leads22 and 23 to the input of control circuit 41. Control circuit 41 mayconsist of two thyristors connected in inverse parallel circuit topermit bi-directional current fiow. A single triac element can be usedinstead of the two thyristors to accomplish the same function. Controlcircuit 41 receives its main current feed from leads 12 and 13 of thethree phase alternating current main over conductors 24 and 25. Theoutput of control circuit 41 is connected over leads 26 and 27 to onewinding of alternating current motor 42. The other winding of motor 42is connected to leads 43 and 44 of the three phase alternating currentmain through conductors 45 and 46. Alternating current motor 42 providesthe rotational drive for spool 4. The two coils of motor 42 receive analternating current displaced in phase by substantially from oneanother. In normal operation, an increase in thread tension wouldcorrespondingly cause semiconductor 38 to plunge deeper into the fieldof magnet 37. The resulting current modification in semiconductor 38acts upon amplifier 18 with controlling effect on circuit 41. In theprocess the feed current to motor 42 would be reduced and the turningrate of spool 4 would decrease. A reduction in thread tension wouldaccordingly bring about an increase in motor current and, thereby, inthe turning rate of the spool.

In FIG. 3, a mechanical-pneumatic damping of regulating device 47 isshown interposed between swinging arm 6 and rotor shaft 7 of the systemdescribed in connection with FIG. 1. In FIG. 4 a mechanical-pneumaticdamping or regulating device 48 is shown interposed between the sensingprong 36 and semiconductor 38 described in connection with FIG. 2. Thedamping device, which will be described in detail later in connectionwith FIG. 5, permits rapid reaction to signficant variations in threadtension but prevents reaction to small tension fiucuations whichnormally occurs.

The damping or regulating device shown in FIG. 5 has an axially slidablefeeler prong 36, one end of which is urged against thread 1 by spring71. The pulling force of spring 71 on feeler prong 36 is adjustable forvarious thread denicrs by means of screw 49 mounted in casing 72. At theother end of the feeler prong 36 there is situated a piston 50 whichmoves in a cylinder 51. From the bottom of cylinder 51 lines areconnected to two valves 52 and 53. Valve 52 closes on the pressurestroke of piston 50. Valve 53 closes on the suction stroke of piston 50and is kept closed at the beginning of the pressure stroke by the biasdetermined by the setting of screw 54 and spring 55. The air forced fromcylinder 51 after valve 53 opens is released through line 56. At point57 on feeler prong 36 there is articulated a lever rod 58. At point 59on rod 58, there are articulated a pressure spring 60 and a piston rod61. Piston 62, which is mounted on piston rod 61, is situated incylinder 63. An outlet 64 which is shown at the bottom of cylinder 63,is provided with adjustable choke 65. The pressure spring 60 issupported on the casing. At point 66, there is articulated a carrier rod67 holding semiconductor 38 such that semiconductor 38 can be moved intothe field of magnet 37. Semiconductor 38 is connected over lines 39, 40,16 and'17 to the input of amplifier 18 (FIGS. 1 and 3). At the upper endof the lever rod 58 there engages a pressure spring 70, which issupported on the casing.

At normal thread tensions, springs 60' and 70 and the pressure exertedby thread 1 on prong 36 counterbalance the effect of spring 71. Piston50, cylinder 51 and valves 52 and 53 perform a damping function suchthat the system does not react to small tension fluctuations, whichalways occur, for example, during the thread distribution process.

If the thread tension variations exceed a predetermined value, then thedamping and regulating member responds. If, for example, a threadtension drop occurs, then the feeler prong 36 is drawn, only slightlydamped by the pulling force of spring 71, against the slackening threadto the right. At the first instant of the tension drop, the point 59 isa fixed pivot point for the lever 58, since the piston 62, because ofits damping action, will not move quickly. Simultaneously then,semiconductor 38 is rapidly drawn into a weaker zone of the field ofmagnet 37. Thereby the current flowing through semiconductor 38 isreduced causing the control circuitry to act upon the magnitude of thefeed current to the drive motor so as to increase its turning rate.After the thread tension drop has stopped, point 57 on prong 36 becomesa pivot point. The piston 62 slides still somewhat further to the rightwhereby semiconductor is plunged into the field of magnet 37 causing areduction in the turning speed of the drive motor.

In the case of an increase in thread tension, the movement of feelerprong 36 can be damped more positively by piston 50 and cylinder 51 thanin the case of a thread tension decrease. The further course of theregulating action then corresponds to that described above.

The damping device operates in such a way that the movement of thefeeler prong 36 first rapidly displaces the semiconductor 38. Theregulating pulse thereby generated changes the turning rate of the drivemotor of the machine. The resetting of the impulse generator that takesplace, however, is damped by reason of the special attuning of the leverarms and forces. As viewed from the standpoint of regulating technology,the regulator presents a proportionabdifferential behavior, because theinitiating command is given proportionally to the displacement of thefeeler prong; but the resetting command for'its return is givendiflerentiated. With reference to the thread, the device acts as aproportional-integral regulator, since the modification of the excursionof the feeler prong is equal to the difierence between the surfaceintegrals of the triangles made by the deflection rollers 2 and 3 andthe thread bend, and because this difference is determined over aproportional member.

The impulse generator described in FIG. 2 consisting primarily of prong36, magnet 37 and semiconductor 38 can also be employed in place of therotary transformer described in connection with FIG. 1 for theregulation of the direct current motor 29. Likewise, the rotarytransformer described in connect-ion with FIG. 1 may be utilized inplace of the impulse generator described in connection with FIG. 2 tocontrol the alternating current motor 42. Furthermore, both the rotarytransformer and the sensing prong with its attached semiconductor can bereplaced by a photoelectrically controlled impulse generator.

In further development of the present invention, the winding ofmaterials other than thread can also be con trolled. Such materialsmight include band-type thread structures, film strips, and the like.Similarly, it is possible to use the regulating system described aboveby sens ing the growing diameter of a winding rather than the threadtension. This type of control is fully suflicient in many cases such asthe rewinding and draw-ofl of thread from a resting delivery bobbin. Itis also possible, to use a program control of known type instead ofsensing the Winding diameter. It is also possible, for example, to use acam plate control in conjunction with other means of thread tensionregulation. The cam plate control would be used for coarse regulation,whereas the fine regulation could be accomplished as a function ofthread tension. Such an approach has the advantage that movements of thedancer roller or sensing prong remains very slight and any possiblethread tension oscillation is avoided.

Obviously m-any modifications and variations of the invention ashereinbefore set forth may be made without departing from the spirit andscope thereof and therefore only such limitations should be imposed asare indicated in the appended claims.

We claim:

1. Regulating apparatus for accurately maintaining a predeterminedthread tension, said apparatus comprising in combination:

(a) a spool means upon which to wind the thread;

(b) a two winding alternating current drive motor;

(c) control means operatively associated with said drive motor, saidcontrol means having an input arranged such that variations in controlsignal levels appearing at said input will cause correspondingvariations in the speed of said motor means, the output side of saidcontrol means being connected to one winding of said alternating currentmotor;

(d) sensing means including an axially movable feeler prong arranged todetect variations in thread tension;

(e) amplifier means having an input and output, the input of saidamplifier means being connected to the output of said sensing means, theoutput of said sensing means being connected to the input of saidcontrol means; and

(f) damping means operatively coupled to said sensing means, saiddamping means comprising in combination with said axially movable feelerprong (1) spring means for holding said feeler prong in contact with thematerial being wound;

(2) a lever means pivotally connected to said feeler (3) a first pistonand cylinder means operatively connected to said lever for providing adamping action on the forward movement of said feeler P .(4) a secondpiston and cylinder means operatively connected to said feeler prong forproviding a damping action on the rearward movement of said feelerprong;

(5) fixed spring means connected to said lever means for positioning andbalancing said lever; and

(6) output means connected to said lever for transmitting the regulatedexcursions of said feeler prong.

2. Regulating apparatus in accordance with claim 1 wherein said controlmeans includes a two thyristor circuit wherein said thyristors arearranged in inverse parallel configuration to permit bi-directionalcurrent flow, the output side of said two thyristor circuit beingconnected to one winding of said alternating current motor.

3. Regulating apparatus in accordance with claim 1 wherein said controlmeans utilizes a triac to achieve bidirectional current flow, the outputside of said tri ac being connected to one winding of said alternatingcurrent motor.

4. Regulating apparatus in accordance with claim 1 wherein said sensingmeans includes:

(a) a pair of roller means in axially spaced relationship;

(b) an axially slidable feeler prong means having two ends, one endarranged to contact the thread between said roller means;

(c) adjustable spring means arranged to urge said feeler prong meansagainst said thread;

References Cited UNITED STATES PATENTS Stack 242-45 Dunigan 318-6 X Ash242-45 Lohest 242-45 X Cohen 242-45 Bonikowski 24245 X STANLEY N.GILREATH, Primary Examiner

